5cha

THE REFINEMENT AND THE STRUCTURE OF THE DIMER OF ALPHA-*CHYMOTRYPSIN AT 1.67-*ANGSTROMS RESOLUTION

spinqualitylabelsall models 5cha, resolution 1.67Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5cha is a 6 chain structure with sequence from Bos taurus. This structure supersedes the now removed PDB entry 3cha. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.67Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CTRA_BOVIN Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The two molecules of the asymmetric unit of the pH 3.5 conformer of alpha-chymotrypsin have been refined at 1.67-A resolution using restrained least squares methods with Hendrickson's program (PROLSQ). The final R factor is 0.179 (including 247 water molecules). The folding of the main chain of the independent molecules is the same within experimental error but the same does not generally apply to the side chain stereochemistry. From this we conclude that the folding of a protein structure is basically independent of most of the detailed stereochemistry of its side chains. The side chains of the interface region between the independent molecules display pronounced asymmetry. This asymmetry suggests that dynamic and asymmetrical structural changes take place at the time of oligomerization leading to more energetically favorable interactions for the dimer. Comparison of the structures of the independent molecules of alpha-chymotrypsin with the structure of monomeric gamma-chymotrypsin revealed that although the folding of the three molecules is essentially the same, numerous and significant differences pervade the side chain stereochemistry attributable to general flexibility. The specificity site of alpha-chymotrypsin is occupied by ordered water molecules in a similar way to gamma-chymotrypsin and other proteins. Some of these water molecules are displaced when substrate binds to the enzyme, while the others appear to help identify and position the aromatic side chain in catalysis. The refinement and the structure of the dimer of alpha-chymotrypsin at 1.67-A resolution.,Blevins RA, Tulinsky A J Biol Chem. 1985 Apr 10;260(7):4264-75. PMID:3980476 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Chymotrypsin 3D structures Streptomyces griseus proteinase B

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